The present invention relates to traps for mounting in a side wall opening of a catch basin side wall.
Catch basins are large concrete structures buried in the ground and used to collect drainage water. They typically have an opening in one side wall to which may be coupled an outflow or outlet pipe of a drainage system. A trap is often provided at the opening in order to prevent floating pollutants, such as gas, oil, leaves and branches, from entering the outlet pipe and possibly plugging the pipe. Such traps may also provide a water xe2x80x9cplugxe2x80x9d for preventing sewer gases from entering the catch basin from the outlet pipe. This reduces offensive odors in the area of the catch basin.
A problem with prior art traps is that they are not particularly effective in filtering or removing matter such as dirt, debris and pollutants from drainage water entering the catch basin. Examples of matter include cigarette butts, fallen leaves, woods, plastic, bottles, trash, sand, and silt, bacteria, heavy metals, nutrients, and hydrocarbons, such as oil and grease. The matter is often carried with the drainage water out of the catch basin and enters lakes and river beds, which can be harmful to aquatic life. Furthermore, outlet pipes downstream of the catch basin may become clogged resulting in costly clean-up operations.
Another problem with conventional traps is that they tend to permit water to flow at too great a rate through the catch basins during periods of heavy rainfall. In some municipalities, drainage water from catch basins combine with sewage water to be collectively treated at sewage treatment facilities. When water entering the sewage treatment plant exceeds its capacity, excess water may go untreated and be discharged into rivers and lakes, resulting in environmental damage.
U.S. Pat. No. 6,126,817 issued Oct. 3, 2000 to Duran discloses traps having flow regulating means which promote the settlement of entrained particles in catch basins. However, the traps are relatively complicated in their design which adds to manufacturing costs. Moreover, the traps are not constructed to remove finer particles such as silt or clay or non-settling pollutants such as hydrocarbons.
The present invention provides a trap which is intended to remedy the above problems and has additional advantages, as will become apparent below.
In accordance with a first aspect of the invention, there is provided an assembly for mounting in a side wall opening of a catch basin side wall and convertible into a trap for reducing the amount of matter being carried out of the catch basin by drainage water exiting the catch basin, said assembly being sealingly attachable across said side wall opening and comprising:
a first trap member having a first wall and an outlet opening formed in said first wall, said first trap member being sealingly attachable to an outlet pipe with said outlet opening in communication with the interior of the pipe;
a second trap member releasably and sealingly engageable with said first trap member and having a second wall spaced from said first wall when so attached; and
a filter assembly releasably attachable to one of said first and second trap members, said filter assembly having a filter member made to capture matter entrained in drainage water;
wherein, when the assembly is assembled, mounted in said side wall opening, and converted into a trap by providing said inlet opening in said second wall at a position below said outlet opening, there is defined a water flow path extending from the catch basin interior, through said inlet opening and then through said outlet opening, and said filter member is positioned across said water flow path to capture matter entrained in drainage water flowing along said path.
The invention also provides an assembly according to the first aspect converted into a trap. When so converted, the second wall has an inlet opening for communicating with the interior of the catch basin. The inlet opening may be sized, shaped and configured to restrict water flow through the assembly to promote settlement of matter in the catch basin.
The second wall may be provided with cutting guides for use in cutting the inlet opening.
In accordance with a second aspect, there is provided a method of capturing matter entrained in drainage water exiting from a catch basin into an outlet pipe through a side wall opening in the catch basin. The method comprises providing a trap that includes an outer trap member having a first wall and an outlet opening formed in the first wall, an inner trap member releasably engaged with the outer trap member and having a second wall defining an inlet opening, and a filter member having an open end and an opposite closed end. The trap is mounted in the side wall opening so that the outer trap member is attached to the outlet pipe and the open end of the filter member is coupled releasably to an inner surface of the outer trap member downstream of the side wall opening. Again, the filter member is made to capture matter from drainage water flowing through the filter member.
Traps according to the present invention have several advantages. First, positioning the filter assembly near the side wall opening of the catch basin, allows the catch basin to be easily cleaned using a conventional vacuum truck. The hose of a vacuum truck can be simply inserted into the catch basin to suck up sediment and debris, without fear of damaging the filter assembly. In contrast, conventional filter assemblies are often mounted near the inlet of the catch basin or within the catch basin itself. In these situations, the filter may be damaged by the hose of a vacuum truck during cleaning. Also, in some cases, the catch basin must be redesigned to accommodate the filter assembly. Furthermore, cleaning such conventional filter assemblies often involves lifting the assemblies out of the catch basin from above, a process which can be time consuming and cumbersome.
Second, by restricting the flow of water through the trap, more particulates are retained in the catch basin as mentioned above. This prevents the downstream clogging of outlet and sewer pipes, and the deposit of sediment in water ways or water bodies such as rivers and lakes.
Third, the present assembly allows for much flexibility, being adaptable after installation to suit site specific needs. The filter assembly and inner trap member may be removed after the trap has been installed to provide a catch basin which functions as though no trap were present. This is useful in situations in which a trap is needed initially but not later. For example, during construction, the inner trap component and filter may be required to keep the large amount of exposed sediment from entering the drainage or sewer system. However, when construction is complete, a catch basin without a trap, or with a trap but without a filter assembly, may be adequate in removing smaller amounts of sediment entering the catch basin. Conversely, the filter assembly and inner trap member may be added to the outer trap member long after the outer trap member has been mounted in the side wall of a catch basin. This is useful in situations in which no trap is needed initially but is needed later. For example, a gas station could be built in an existing community near a catch basin with no trap. With the outer trap member already installed in the catch basin side wall, one could simply mount the inner trap member to the outer trap member during construction of the gas station to provide a trap suitable for catching large sediments resulting from construction. A filter assembly suitable for capturing particulate matter could also be mounted to catch finer sediments. Later, when the gas station is operational, the filter assembly may be replaced with another filter assembly having a hydrocarbon filter to filter gasoline and oil from drainage water entering the trap from the gas station.
A fourth arguable advantage is that the catch basin will xe2x80x9cback upxe2x80x9d when the filter is clogged thereby providing a visual indicator that the filter needs replacement. This is in contrast with some conventional filter assemblies which provide overflow openings to allow water to flow into the drainage system when the filter is clogged, thus carrying dirt, debris and other pollutants with it.